Rotator Cuff Delamination Is Associated With Increased Tendon Retraction and Higher Fatty Muscle Infiltration: A Comparative Study on Arthroscopy and Magnetic Resonance Imaging.

PURPOSE: To investigate (1) tendon delamination according to different rotator cuff tear patterns as well as (2) the association of tendon retraction and fatty muscle infiltration with delamination of the rotator cuff. Furthermore, we aimed to establish the accuracy of magnetic resonance imaging for the detection of rotator cuff delamination. METHODS: Magnetic resonance imaging scans of patients who underwent arthroscopic rotator cuff repair from 2013 to 2015 were retrospectively compared to intraoperative findings. Prevalences of tendon delamination, tendon retraction, and fatty muscle infiltration were categorized according to different rotator cuff tear patterns. For comparability of the amount of tendon retraction of delaminated and non-delaminated rotator cuff tears, we introduced the global retraction index, a description individually assessing tendon retraction in magnetic resonance imaging scans of all visible layers. RESULTS: Of 349 shoulders, tendon delamination was observed in 231 patients (66.2%). Of these, rotator cuff delamination was most commonly seen in posterosuperior rotator cuff tears (84.6%). Delaminated rotator cuff tears presented with a significantly higher global retraction index (P < .001) as well as higher fatty muscle infiltration of the supraspinatus (P = .001) and infraspinatus (P = .001). Magnetic resonance imaging had only moderate accuracy (57.3%) to detect rotator cuff delamination, with a positive predictive value of 100% (95% confidence interval [CI] 95.6% to 100.0%) and a negative predictive value of 44.2% (95% CI 38.1% to 50.4%). CONCLUSIONS: Tendon delamination was most commonly observed in posterosuperior rotator cuff tears. Delaminated rotator cuff tears showed a significantly greater tendon retraction as well as a higher amount of fatty muscle infiltration of the supraspinatus and infraspinatus. Magnetic resonance imaging has only moderate accuracy for detection of rotator cuff delamination. LEVEL OF EVIDENCE: III, retrospective cohort study.

Return to Sport and Patient Satisfaction at 5-Year Follow-up After Nonoperative Treatment for Acute Achilles Tendon Rupture.

BACKGROUND: There is controversy whether nonoperative or operative treatment for Achilles tendon rupture is superior. It is unknown if patients with acute Achilles tendon rupture return to previous sports activity. The purpose of this study was to assess 5-year return to sport and subjective satisfaction, minimum 1-year functional outcomes, and complications in patients following nonoperative treatment of Achilles tendon rupture with early weightbearing rehabilitation. METHODS: An institutional review board-approved, retrospective observational study involving 89 patients was performed. Out of 114 consecutive patients, 89 (78%) responded to questionnaires for sports activity. Nonoperative treatment consisted of an equinus cast and rehabilitation boot that enabled early weightbearing. Sports activity at 1-year and 5-year follow-up was compared to the prerupture status. Based on the prerupture Tegner Activity Scale (TAS), patients were divided into low-level (<6) and high-level (≥6) activity groups. Clinical assessment at minimum 1-year follow-up was performed with the Thermann score. Mean clinical follow-up was 34 ± 23 months. RESULTS: Overall, >70% of the patients returned to their previous sports activity level after a nonoperative early weightbearing treatment. Return-to-sport rate was significantly (P = .029) higher for patients in the low-level activity group (91%) compared to patients (67%) in the high-level activity group at 5-year follow-up. Subjective satisfaction with treatment was good in both groups (93% and 96%, respectively). The mean Thermann score did not differ between the 2 groups at 1-year follow-up. There were 11 reruptures, 5 deep venous thromboses, and 1 case of complex regional pain syndrome. CONCLUSION: Nonoperative treatment for Achilles tendon rupture yielded good functional outcome and high patient satisfaction. For patients with a high preinjury activity level, return to previous sporting level (assessed by TAS) was possible in 67% of the patients compared to >90% of patients with low preinjury activity level. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Compression sonography for non-invasive measurement of lower leg compartment pressure in an animal model.

INTRODUCTION: Compression ultrasound is a non-invasive technique allowing for qualitative visualization and quantitative measurements of mechanical tissue properties. In acute compartment syndrome (ACS), cadaver studies have proven that the intra-compartmental pressure (ICP) measured by compression sonography correlates with the ICP measured invasively. This study aimed to evaluate compression sonography for compartment pressure measurements in an animal model. MATERIAL AND METHODS: The pressure in the anterior tibial compartment of 6 domestic pig legs was increased from baseline to 40mmHg in 5mmHg steps. Using compression sonography, the compartment diameter was measured without external pressure and during manual application of five levels of external pressure. The elasticity ratio (ER) was computed as the ratio of the compartment diameter with and without external pressure. At 40mmHg of external pressure the ERs at different ICP levels were compared using repeated ANOVA measurements. Post-hoc comparisons evaluated the lowest detectable ICP fulfilling the definition of ACS (ICP≥30mmHg) by starting from each pressure below 30mmHg (baseline, 20mmHg and 25mmHg, respectively). Receiver operator characteristic analyses defined ER limits with appropriate sensitivity and specificity to detect ACS. RESULTS: The ER increased from 79.0% at baseline ICP to 89.3% at 40mmHg ICP. The ER at baseline and at 20mmHg ICP significantly differed from the ER at 30mmHg ICP (p=0.007 and 0.002, respectively); the ER at 25mmHg ICP significantly differed from the ER at 40mmHg ICP (p=0.001). An ER less than 87.1% had a sensitivity of 94.4% and a specificity of 88.9% to proper diagnosis of ACS. CONCLUSION: Compression sonography might offer a non-invasive technique to guide treatment in cases of uncertain acute compartment syndrome. Further studies are needed to collect elasticity ratio data in humans and to clinically validate compression sonography for compartment pressure measurements.